Washable rugs

ABSTRACT

WASHABLE RUGS HAVING IMPROVED DURABLE SKID-RESISTANCE COMPRISING A RUG FACING AND AN ELASTOMERIC BACKING ARE DESCRIBED. THE ELASTOMERIC BACKING COMPRISES A COPOLYMER OF A CONJUGATED DIENE WITH A VINYL COMPOUND AND CONTAINING A NICKEL SALT OF A DIALKYLDITHIOCARBAMIC ACID. IT HAS BEEN FOUND THAT THE INCORPORATION OF THE NICKEL SALT SIGNIFICANTLY IMPROVES THE DURABILITY OF THE SKID RESISTANCE OF THE RUG TO AGING AND WASHING.

United States Patent 3,681,130 WASHABLE RUGS Samuel J. Hagley, Jr., Spartauburg, S.C., assignor to llggering Milliken Research Corporation, Spartanburg, No Drawing. Filed Apr. 17, 1970, Ser. No. 29,706 Int. Cl. D05c 17/00 U.S. Cl. 117-143 A 15 Claims ABSTRACT OF THE DISCLOSURE Washable rugs having improved durable skid resistance comprising a rug facing and an elastomeric backing are described. The elastomeric backing comprises a copolymer of a conjugated diene with a vinyl compound and containing a nickel salt of a dialkyldithiocarbamic acid. It has been found that the incorporation of the nickel salt significantly improves the durability of the skid resistance of the rug to aging and washing.

BACKGROUND OF THE INVENTION This invention relates to washable rugs having improved durable skid resistance, and more particularly, to washable rugs of the type used for removing dust and other particles from the shoes of persons entering buildings and offices.

Rugs and mats conventionally are produced by coating the back side of a facing material with a backing layer of a rubber-like material. Various rubber-like materials have been suggested as being useful in forming the backing for rugs, mats and carpets. In addition to helping to hold the rug components together through an adhesive action, the backing also serves to provide the rug or mat with a resistance to skidding while in use.

The facing fabric generally comprises a plurality of yarns tufted to one side of a fabric by well known tufting techniques. An example of such a facing fabric would be a cotton shag prepared by tufting cotton yarns into a cotton duck backing fabric. The dust collecting properties of mats and rugs can be improved by providing the tufted yarns with a dust collecting oil which is used in an amount sufficient to absorb or hold dust.

After extended use, the rugs and mats become soiled to various degrees depending upon the extent of use and the location of the mat. Therefore, it is necessary that these mats and rugs be capable of being laundered in any type of industrial laundry so that they may be reused. They are generally subjected to washing conditions of from about 140 to 200 F. using soaps or detergents, alkalies, water softeners, etc. They are then rinsed and dried at elevated temperatures utilizing gas driers, steam driers or electric driers. Since the rugs and mats of the type described in this application will be subjected to such laundering techniques, it is necessary that the rugs be capable of being washed repeatedly without significant loss of its desirable properties, particularly, its ability to resist skidding while in use. Although the dust collecting properties of the rugs can be renewed by replacing the dust collecting oil, the loss of skid resistance results from a deterioration of the rubber-like backing and it is feasible to minimize a loss of this property by a subsequent surface treatment but at a significant expense.

Attempts have been made to vary the nature of the rubber-like backing to provide backings whose properties are more durable to washing. Nitrile latices have been used extensively in rug backings since they have many commercially desirable characteristics. Polymers and copolymers of conjugated dienes also have been used ex- 3,681,130 Patented Aug. 1, 1972 "ice SUMMARY OF THE INVENTION These problems have been overcome by providing rugs comprising a rug facing and a non-skid elastomeric backing comprising a copolymer of a conjugated diene with a vinyl compound and having dispersed therein, a small amount of a nickel salt of a dialkyldithiocarbamic acid. Rugs or mats prepared in this manner can be subjected to repeated washing while maintaining an improved degree of skid resistance while in use. Petroleum, dust collecting oils can be applied to the rug facing to improve the dust-collecting properties of the rugs.

DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention is concerned with washable rugs, carpets and mats which, for convenience, will hereinafter be referred to as either rugs or mats. The rugs of this invention are those comprising a rug facing and a nonskid elastomeric backing. The rug facing may be any of the Well known facings including, for example, cotton shags prepared by tufting cotton yarn in a cotton fabric such as cotton duck. Rug facings comprising cellulosic yarns tufted on one side of a cotton duck fabric are particularly preferred for preparing washable dust-collecting rugs where a petroleum, dust collecting oil is applied to the tufted yarns. It is preferred generally that the fabric be resistant to shrinkage during washing. Such shrinkproofed fabrics can be prepared either through selection of yarn, construction or through the application of known shrinkproofing techniques. Generally, fabrics having a shrinkage potential of between 0 and 15% are useful, and fabrics having a shrinkage potential of from 0 to 5% are preferred.

The elastomeric backing which is utilized in the rugs of this invention are those comprising a copolymer of a conjugated diene with a vinyl compound. The conjugated dienes are those having from 4 to 6 carbon atoms per molecule of diene monomer. Examples of such dienes include 1,3-butadiene, 1,3-pentadiene and 1,3-hexadiene. Examples of the vinyl compounds include such compounds as styrene, nuclear-substituted alkyl styrenes such as 0-, m-, and p-methyl styrene; nuclear-substituted halostyrenes such as 2,4-dichlorostyrene; acrylonitrile; acrylic acid; allyl chloride; and vinyl esters such as vinyl acetate, vinyl propionate, vinyl stearate, etc.

Copolymers of acrylonitrile and conjugated dienes such as 1,3-butadiene, have been used extensively in rug backings. These copolymers generally contain from about 20 to 60% by weight of acrylonitrile and from about 40 to 80% of the butadiene. Examples of such commercially available nitrile latices include Hycar available from B. F. Goodrich Company; Butaprene available from Firestone Company and Nitrex available from Naugatuck Chemical Division of US. Rubber Co.

Examples of such copolymers of conjugated dienes include copolymers comprising: butadiene and 25% styrene; 75% 1,3-pentadiene and 25 styrene; 55% 1,3-butadiene and 45% acrylonitrile; 78% butadiene and 3 22% acrylonitrile; and 67% 1,3-butadiene and 33% acrylonitrile.

As mentioned above, the skid resistance of rugs having the above-described elastomeric backing is improved by the incorporation therein of small amounts of a nickel salt of a dial kyldithiocarbamic acid. The improved skid resistance especially is evident after the rug has been used for a period of time and has been subjected to several washings. It usually is at this time that the rug backing has deteriorated to the point where there is essentially no noticeable skid resistance. However, when from about 0.05 to 6% by weight based on the weight of the elastomer of a nickel salt of the dialkyldithiocarbamic acid has been incorporated into the elastomer, a noticeable improvement in the permanence of the skid resistance to aging is observed. The nickel salts which are utilized in the present invention are those in which the alkyl groups contain up to about 8 carbon atoms. The alkyl groups may be linear or branched chain groups and either primary, secondary or tertiary. Mixtures of alkyl groups also are useful. Examples of such salts include nickel diethyldithiocarbamate, nickel dibutyldithiocarbamate, nickel diisopropyldithiocarbamate, nickel diallyldithiocarbamate and nickel di 2-ethylhexyldithiocarbamate. Although larger amounts may be utilized, the incorporation of from about 0.5 to 2% of the nickel salt in the elastomer provides the desired results.

In addition to the nickel salt of the dialkyldithiocarbamic acid, a rug having improved properties, particularly with respect to reduced thermal degradation, is obtained by the incorporation in the elastomer of finely divided carbon black. Any of the well known finely divided carbon blacks utilized in the rubber industry are satisfactory. Generally, amounts up to about 7.5% may be incorporated in the elastomeric backing.

The rugs and mats of the present invention are prepared by applying a latex of the elastomer to the mat or rug facing by procedures well known in the art. The aqueous latex may contain in addition to the copolymer and nickel salt (and, optionally, carbon black), the usual latex stabilizer and additives such as antioxidants, antifoaming agents, vulcanizing agents, dispersing agents, thickeners, cure activators and other optional ingredients utilized to modify the physical properties and cost. Materials suitable for these purposes are well known in the art.

The nickel salt of the dialkyldithiocarbamic acid may be added to the latex during its preparation or immediately before application of the latex to the face fabric. The vulcanizing agent, usually sulfur, is added to the latex just before the latex is applied to the mat. The viscosity of the latex may be varied to a consistency best suited for coating the particular mat by use of thickeners or thinners. Generally, viscosities of about 3500 cps. as determined on a Brookfield Viscometer using a spindle No. 4 at 6 rpm. are acceptable.

The proportion of the elastomeric backing applied to the mat may range from about to about 15 ounces per square yard upon a solids basis. The latex may be cured, with sulfur as a vulcanizing agent, at a temperature of about 290 F. for 15 minutes.

The following examples will illustrate some elastomeric latex formulations useful in preparing the rugs of the invention.

EXAMPLE I Parts by weight Good-Rite 2570X1 (a 51% solids styrene-butadi- EXAMPLE II Parts by weight Butadiene-acrylonitrile (55:45) copolymer latex copolymer latex (50% solids) N-phenyl-a-naphthylamine 1.0 Stearic acid 1.5 Zinc oxide 1 5.0 Zinc salt of Z-mercapto benzothiazole 1.5 Sulfur 1.5 Nickel dibutyl dithiocarbamate 2.0

EXAMPLE III Parts by weight Butadiene-acrylonitrile (55 :45 copolymer latex The dust collecting properties of rugs and mats prepared in accordance with the procedures described above may be improved by applying a dust collecting oil on the face of the rug. Any of the petroleum dust collecting oils presently used in preparing dust collecting fabrics, mops and mats are satisfactory. In general, the petroleum oils should have a boiling point range above about 500 F. and an aniline point of above about 180 F. A suflicient amount of the oil is supplied to the carpet or mat to provide an absorption of about 0.075 to 1.0 ounce of oil per square foot surface area of the mat or rug. When the soiled mats are laundered, the oil which is removed in the laundering is replaced by an equivalent amount of a similar oil after laundering.

That which is claimed is:

1. A washable rug having improved durable skid resistance comprising a rug facing and a non-skid elastomeric backing comprising a copolymer of a conjugated diene with a vinyl compound, said conjugated diene having from 4 to 6 carbon atoms per molecule of diene monomer, said elastomeric backing having dispersed therein from about 0.05 to 6%, based on the weight of the elastomer, of a nickel salt of a dialkyldithiocarbamic acid in which the alkyl groups contain up to 8 carbon atoms.

2. The rug of claim 1 wherein the facing comprises a plurality of cellulosic yarns tufted to one side of a cellulosic fabric having a potential shirinkage of from 0 to about 15%.

3'. The rug of claim 2 whereon the tufted yarns have a petroleum, dust collecting oil absorbed thereon.

4. The rug of claim 3 wherein the dust collecting oil has an aniline point above about 180 F. and a boiling point of above about 500 F.

5. The rug of claim 1 wherein the conjugated diene is a. butadiene.

6. The rug of claim 1 wherein the elastomeric backing comprises a copolymer of from about 20 to 60% acrylo nitrile with from about 40 to 80% of a butadiene.

7. The rug of claim 1 wherein the elastomeric backing also has from about 0.05 to 7.5 of finely divided carbon dispersed therein.

8. A washable dust collecting mat having skid resistance of improved durability comprising a facing of a plurality of yarns tufted to one side of a fabric having potential shrinkage of from about 0 to 15% and an elastomeric backing comprising a copolymer of a conjugated diene with a vinyl compound, said conjugated diene having from 4 to 6 carbon atoms per molecule of diene monomer, said elastomeric backing having incorporated therein, from about 0.05 to 7.5% of finely divided carbon and from about 0.05 to 6% of a nickel salt of a dialkyldithiocarbamic acid in which the alkyl groups contain up to about 8 carbon atoms.

9. The dust collecting mat of claim 8 wherein the elastomeric backing comprises a copolymer of from about 20 to 60% of acrylonitrile and from about 40 to 80% of a butadiene.

10. The dust collecting mat of claim 9 wherein the butadiene is 1,3-butadiene.

11. The dust collecting mat of claim 8 wherein the dialkyldithiocarbamic acid is dibutyl dithiocarbamic acid.

12. The dust collecting mat of claim 8 wherein the facing comprises a plurality of cellulosic yarns tufted to one side of a cellulosic fabric.

13. The dust collecting mat of claim 12 wherein the tufted cellulosic yarns have a petroleum, dust collecting oil absorbed thereon.

14. The dust collecting mat of claim 13 wherein the amount of absorbed oil is from about 0.075 to 2.0 ounces per square foot of surface area of the mat.

15. The dust collecting mat of claim 12 wherein the cellulosic fabric in the facing is cotton duck having a potential shrinkage from 0 to about 5%.

References Cited UNITED STATES PATENTS 3,306,808 2/ 1967 Thompson et a1 16166 3,227,574 1/ 1966 Mohr 161-66 UX 3,505,156 4/ 1970 Handscomb et a1. 16166 3,414,458 12/1968 'Lacy 161-66 3,486,920 12/1969 Campbell et al 161-66 3,553,047 1/19T1 Godden 16 1--66 OTHER REFERENCES G. Alliger et al. (ed.): vulcanization of Elastomers, Reinhold Publishing Corp., New York, 1964, pp. 156-159 relied on.

15 ROBERT F. BURNETT, Primary Examiner R. O. LINKER, Jr., Assistant Examiner US. Cl. X.R. 

